Welcome to the ranks of Bigfoot
You have reason to be excited!
Actually you have a 17' Bigfoot, not a 17.5'.
Your actual model designation for that trailer is a 15B17G or 15B17CB indicating a 1500 series, 17 foot, rear bath/side gaucho arrangement. The center bath models are indicated by a CB instead of the G. The 175s which are the 2500 series bodies were first produced in 2005.
I have an '04 15B17CB and an '06 25B25RQ and my neighbor (and Pastor) has a '93 15B19G tandem axle! We probably have the market cornered on Bigfoot trailers in the midwest! In epidemiology, they call that a cluster, so I guess we have a Bigfoot cluster in our neighborhood?
If there's anything I can help with, please let me know.